"In line with the currently acting sale and purchase agreement between Gazprom and Naftogaz Ukrainy, starting from 4 pm February 19, 2015 Gazprom supplies 12 million cubic meters of gas a day to Ukraine, including via gas measuring units of Prokhorovka and Platovo," Miller said.

Earlier on Thursday Russian Prime Minister Dmitry Medvedev ordered to provide assistance to the citizens of Debaltsevo and other settlements in the Ukrainian conflict zone that are facing a humanitarian crisis. PM ordered the Energy Ministry and Gazprom to prepare proposals on humanitarian gas supplies to south-east Ukraine.

"There is still another problem relating to gas supplies: by decision of the Ukrainian authorities, in any case, by the decision that has not yet been cancelled, and as a result of their certain actions, gas is not supplied to the territory of a whole number of populated areas [in south-east Ukraine — TASS]. Despite the calls for gas supplies, this is not taking place," Medvedev said.

"I would like the Energy Ministry to prepare proposals jointly with Gazprom on providing humanitarian aid through gas supplies for the needs of these regions, unless urgent measures are taken for their provision with gas using the customary scheme," Medvedev said.

Meanwhile, spokeswoman for the Russian premier Natalia Timakova said that humanitarian gas supplies to south-east Ukraine will be commercial.

"Gazprom will supply gas to the south-east [of Ukraine] as humanitarian aid on a commercial basis. The sources of financing are being determined," she said.

A source familiar with the situation said financing could possibly be provided through a loan or some other option.